1. When You're Stressed...

Eat This:
1 Cup of Low-Fat Yogurt or 2 Tbsp of Mixed Nuts

Scientists in Slovakia gave people 3 grams each of two amino acids — lysine and arginine — or a placebo and asked them to deliver a speech. Blood measurements of stress hormones revealed that the amino acid–fortified public speakers were half as anxious during and after the speech as those who took the placebo. Yogurt is one of the best food sources of lysine; nuts pack tons of arginine.

Not That!
A Can of Soda

A study from the American Journal of Public Health found that people who drink 20 ounces of soda daily are three times more likely to be depressed and anxious, compared with those who drink less.

2. When You Want to Increase Your Metabolism...

Drink This:
Green Tea

Catechins, the powerful antioxidants found in green tea, are known to stoke your metabolism, making it burn hotter and torch more calories. A study by Japanese researchers found that participants who consumed 690 milligrams of catechins from green tea daily had significantly lower body-mass indexes and smaller waist measurements than tea-totalers (i.e., they avoid the stuff).

Not That!
Nothing

Skipping meals lets your body's calorie-burning furnace go cold. Spread out snacks throughout the day. Try a cup of yogurt with fresh fruit or almonds between breakfast and lunch, and a hard-boiled egg or hummus with vegetables in the afternoon.

3. When You're Low on Energy...

Eat This:
A Handful of Trail Mix

Raisins provide potassium, which your body uses to convert sugar into energy. Nuts stock your body with magnesium, which boosts metabolism and improves nerve and muscle function. (When magnesium levels are low, your body produces more lactic acid — the same fatigue-byproduct that makes your muscles ache at the end of a workout.)

Not That!
Espresso-Based Drinks

Sure, the caffeine will perk you up, but the spike in blood sugar that follows — with anywhere from 16 grams (latte) to 59 grams (white chocolate mocha) of sugar coursing through your veins — will ultimately launch your own personal energy crisis. Stick to brewed coffee with one packet of sugar, max.

4. When You Need a Brain Boost...

Eat This:
Blueberries

Antioxidants in blueberries help protect the brain from free-radical damage, which could decrease your risk of Alzheimer's and Parkinson's diseases, and improve cognitive processing. Wild blueberries, if you can find them (or grow them!), have even more brain-boosting antioxidants than the cultivated variety.

Not That!
Ice Cream

Sugary foods incite sudden surges of blood glucose that, in the long term, cause sugar highs and lows, and make you as distractable as a toddler in the Disney store. And foods high in saturated fat can clog blood vessels and slow the flow of nutrients and blood to the brain.

5. When You're Under the Weather...

Drink This:
Ginseng Tea, Hot or Iced

In a Canadian study, people who took 400 milligrams of ginseng a day had 25 percent fewer colds than people who popped a placebo. Ginseng helps kill invading viruses by increasing the body's production of key immune cells.

Not That!
Caffeinated Beverages and Energy Drinks (oops.. i often drink my fav POCARI ! that explains)

Excessive caffeine messes with your sleep schedule and sabotages key immune agents. And insufficient sleep opens the door to colds, upper respiratory infections, and other ills. What's more, caffeine can dehydrate you, and hydration is vital during illness: Fluids not only transport nutrients to the problem zones, but also carry away toxins.

6. When You Need to Wake Up and Go...

Eat This:
Eggs and Whole-Wheat Toast

Eggs are a great source of protein, and having them for breakfast sets you up for a perfect day of eating. Saint Louis University researchers found that people who eat eggs for breakfast consume 264 fewer calories the rest of the day than those who eat bagels and cream cheese.

Not That!
Bagel and Cream Cheese

At 500 calories and 20 grams of fat, this deli disaster is one of the worst ways to start your day. Sixty grams of fast-burning carbohydrates will cause a dip in energy and a spike in hunger, long before lunchtime. The same goes for croissants, danish, donuts, and pancakes.

7. When You Want to Get ''In the Mood''...

Eat This:
Dark Chocolate

The cocoa in chocolate contains stimulants that increase your body's sensitivity. Chocolate also contains phenylethylamine, a chemical that can give you a slight natural high. And Italian researchers found that women who often eat chocolate have a higher sex drive than those who don't. Make sure your chocolate has at least 60 percent cacao.

Not That!
The Third Glass of Wine

The alcohol in wine affects your prefrontal cortex, which can decrease inhibition and up your sexual appetite. But only for the first glass or two. Beyond that, the toxic affects of alcohol in your system take over and are as likely to make you sleepy as they are to make you sexy. The more pouring, the more snoring.